求类内离散度矩阵py
时间: 2023-06-21 22:09:59 浏览: 56
以下是求解类内离散度矩阵的Python代码:
```python
import numpy as np
def within_class_scatter_matrix(X, y):
n_features = X.shape[1]
labels = np.unique(y)
n_classes = len(labels)
S_W = np.zeros((n_features, n_features))
for cl in labels:
X_cl = X[y == cl]
mean_cl = np.mean(X_cl, axis=0)
S_cl = np.zeros((n_features, n_features))
for x in X_cl:
x = x.reshape(n_features, 1)
mean_cl = mean_cl.reshape(n_features, 1)
S_cl += (x - mean_cl).dot((x - mean_cl).T)
S_W += S_cl
return S_W
```
其中,参数X是一个大小为(n_samples, n_features)的矩阵,代表数据集中的样本特征;参数y是一个大小为(n_samples,)的向量,代表数据集中的样本标签。函数返回的是类内离散度矩阵S_W,大小为(n_features, n_features)。